By casting zone of silence, you manipulate sound waves in your immediate vicinity so that you and those within the spells area can converse normally, yet no one outside can hear your voices or any other noises from within, including language-dependent or sonic spell effects. This effect is centered on you and moves with you. Anyone who enters the zone immediately becomes subject to its effects, but those who leave are no longer affected. Note, however, that a successful Spot check to read lips can still reveal whats said inside a zone of silence.

Creatures within the emanation area (or those who enter it) can't speak any deliberate and intentional lies. Each potentially affected creature is allowed a save to avoid the effects when the spell is cast or when the creature first enters the emanation area. Affected creatures are aware of this enchantment. Therefore, they may avoid answering questions to which they would normally respond with a lie, or they may be evasive as long as they remain within the boundaries of the truth. Creatures who leave the area are free to speak as they choose.